EBUS procedures have been used for many years and allow thoracic surgeons and physicians to use a bronchoscope or endoscope to be inserted and guided through a patient's mouth and trachea and with the scope fitted with an ultrasound processor and a fine gauge aspiration needle is guided through a portion of the scope. Once appropriately positioned, the needle portion of the fine needle aspiration device is advanced into a lymph node or other lesion, the sample is aspirated and the device is removed from the bronchoscope. Such devices pay an increasingly important part in the role of diagnosis and staging of thoracic malignancies.
Conventionally, when biopsies were desired to be taken of the lymph nodes, for example, to aid in the diagnosis of carcinoma, the prior techniques would typically utilize a substantially rigid needle and penetrate the body via percutaneous entry. For example, U.S. Pat. Nos. 3,630,192 and 3,628,524 each to Jamshidi disclose biopsy needles suitable for percutaneous entry. More recently, less invasive flexible biopsy instruments which do not require percutaneous entry have been described. U.S. Pat. No. 4,249,541 to Pratt discloses that a flexible biopsy instrument can be utilized in combination with a fiberoptic bronchoscope.
The foregoing Wang patents relate to a first approach in designing a completely flexible bronchoscopic needle assemblies wherein relatively non-invasive biopsy procedures can be performed utilizing the needle in combination with a fiber optic bronchoscope. The attending physician inserts the bronchoscope into a predetermined one of the patient's natural orifices depending upon the particular organ desired to be biopsied. The needle assembly, which includes an outer catheter and an inner coaxial stylus attached to a retractable needle, is slidably inserted into a receiving passageway of the bronchoscope. The distal end of the needle assembly is urged against tissue, for example the lung's interior wall, and when the needle was pushed out of the needle assembly it would pass into the tissue of the patient, and by using a stabbing force exerted on the proximal end of the stylus (e.g. the end on the exterior of the patient's body), the tissue of the area being penetrated cold be obtained. The bronchoscope enables the attending physician to accurately position the needle and to penetrate the exact location of the desired organ due to the viewing capabilities provided thereby.
A particular problem in utilizing a flexible bronchoscopic needle is that the needle assembly must be flexible enough to allow the physician to maneuver the assembly through the patient's orifice to the target site, but rigid enough to allow penetration of the collection device, such as a needle, into the target tissue. The bronchial wall or hard tumor tissue will need to be penetrated and thus may present significant resistance to entry of the needle. Upon arrival at the target site, the needle assembly, particularly the distal portion of the needle assembly, should be rigid enough to provide a countering pressure against the resistance provided by the bronchial wall or hard tumor tissue or both together. Conventional needle assemblies have not provided a satisfactory means for balancing the necessary flexibility with the desired rigidity as the needle is extended into the target tissue. Thus, a need exists for a needle assembly having flexible characteristics as the assembly is maneuvered through the bronchoscope or a patient's orifice while having rigid characteristics as the needle is inserted into the target tissue.
When obtaining a biopsy of a patient's tissue, it is often desirable for the bronchoscopic needle to penetrate the target site in a perpendicular direction to minimize the length of the penetration into the patients' tissue, and to reduce patient healing time. Another problem with conventional bronchoscopic needles is that the length of the needle may hinder the ability of the needle to enter a target site in a direction perpendicular to the target site wall because the length of conventional needles limits the flexibility of the distal end of conventional flexible bronchoscopic needle assemblies. Thus, a need also exists for a needle assembly having the ability to appropriately penetrate a target site wall in a direction substantially perpendicular to the target site wall.